Molecular identification of clearwing moth species on landscape trees in Isfahan and determination of their infestation intensity on different tree species

The Clearwing moths (Lep.: Sesiidae) are important and destructive pests of fruitful and non- fruit bearing trees in different countries of the world. Considering the high damage of sesiid moths in Isfahan landscape, the infestation percentage and intensity were studied on 4768 trees of different species in 14 Isfahan municipality regions, Isfahan University of Technology campus and Nazhvan parks as 15th and 16th regions, respectively.  To identify sesiid moth species, DNA was extracted from larvae and adults. Polymerase Chain Reaction (PCR) was used to amplify a 709-bp region of the mitochondrial DNA cytochrome oxidase I and samples were sequenced. Results of COI sequences revealed that the moth Synanthedon caucasica (Gorbunov) is the damaging species on Platanus orientalis, Ulmus carpinifolia and U. carpinifolia var umbraculifera and the sesiid moth Sesia pimplaeformis (Oberthür) (=Eusphecia pimplaeformis) is harmful to Salix alba and Populus alba. Percentage of infestation was calculated based on the number of infested trees divided by total trees and intensity of infestation was determined based on the total number of pupal exuviae, active larval holes and inactive larval holes per 10 centimeters of trunk diameter. The combined analysis was performed in a completely randomized design with 10 replicates. The regions and hosts were considered as main and secondary factors, respectively. Using linear regression between tree diameter and infestation rate, the effect of trunk diameter on the infestation rate was determined. Results showed that 53.8 % of Platanus orientalis, 65.6% of U. carpinifolia, 64.4% of U. carpinifolia var umbraculifera, 52.6% of S. alba and 45.2% of P. alba and totally 53.2% of all trees were infested with sesiid larvae. The highest infestation intensity (4.2) was observed on U. carpinifolia var umbraculifera. The species U. carpinifolia, Platanus orientalis, salix alba and P. alba had lower infestation intensity. No sesiid damage symptoms were observed on Morus spp., Rubinia pseudoacacia and Fraxinus rotundifolia subsp. persica. On all host tree species, the correlation between trunk diameter and infestation rate was positive but a significant correlation (p < 0.05) was only occurred in U. carpinifolia var umbraculifera and salix alba.